2 files changed, 39 insertions, 0 deletions
diff --git a/day11/day11.hs b/day11/day11.hs
new file mode 100644
index 0000000..cf1c4e0
--- /dev/null
+++ b/day11/day11.hs
@@ -0,0 +1,38 @@
+import Data.List
+
+type Stone = Int
+
+atoi :: String -> Stone
+atoi = read
+
+maybeSplitDigs :: Stone -> Maybe (Stone, Stone)
+maybeSplitDigs s
+  | even ln = Just (s `divMod` md)
+  | otherwise = Nothing
+  where
+    ln = ceiling $ logBase 10 $ fromIntegral s
+    md = 10 ^ (ln `div` 2)
+
+blink :: [Stone] -> [Stone] -> [Stone]
+blink acc [] = reverse acc
+blink acc (h:t)
+  | h == 0 =
+      blink (1:acc) t
+  | h == 1 =
+      blink (2024:acc) t
+  | Just (left, right) <- maybeSplitDigs h =
+      blink (right:left:acc) t
+  | otherwise =
+      blink (h * 2024:acc) t
+
+consume :: String -> [Stone]
+consume = map atoi . words
+
+part1 :: [Stone] -> Int
+part1 = length . last . take 26 . iterate (blink [])
+
+main = do
+  file <- readFile "day11.input"
+  let stones = consume file
+  putStrLn ("Part 1: " ++ (show $ part1 stones))
+  --putStrLn ("Part 2: " ++ (show $ part2 mp))
diff --git a/day11/day11.input b/day11/day11.input
new file mode 100644
index 0000000..6a94b4e
--- /dev/null
+++ b/day11/day11.input
@@ -0,0 +1 @@
+872027 227 18 9760 0 4 67716 9245696